Arrive at rooftop bars before 20:30 in summer
The Eurostars Gran Vía rooftop and bHeaven both fill from 20:30 onward in June through August. Arriving at 19:30 or 20:00 means you can choose your seat rather than taking whatever is left. The light at that hour is also better for the Alhambra view than it is after dark, when floodlighting flattens the palace's texture.